Long afterglow silicate luminescent material and its manufacturing method

ABSTRACT

The long afterglow silicate luminescent materials which main chemical composition formula is: aMO-bM&#39;O-cSiO 2  -dR:Eu x  Ln y , wherein M represents one or more elements selected from a group consisting of Sr, Ca, Ba and Zn; M&#39; represents one ore more elements selected from a group consisting of Mg, Cd and Be; R represents one or two components selected from B 2  O 3  and P 2  O 5  ; Ln represents one or more elements selected from a group consisting of Nd, Dy, Ho, Tm, La, Pr, Tb, Ce, Mn, Bi, Sn and Sb; a, b, c, d, x and y are mole coefficients; wherein 0.6≦a≦6, 0≦b≦5, 1≦o≦9, 0≦d≦0.7, 0.00001≦x≦0.2, and 0≦y≦0.3; these luminescent materials have long afterglow characteristic after absorbing short wavelength lights.

This invention relates to long afterglow luminescent material and more particularly to long afterglow silicate luminescent material and its manufacturing method.*

BACKGROUND OF THE INVENTION

Since its invention in the nineteenth century, the traditional long afterglow phosphors of ZnS series have been improved greatly, several typical products have been produced, including ZnS:Cu (which emits green light), (CaSr)S:Bi (which emits blue light) and (ZnCd)S:Cu (which emits yellowish-orange light), and they have been applied in some commercial fields, however the shortcoming of these phosphors were: poor stability, easy to decompose in air, easy to turn gray even black when irradiated under sun light, only 0.5-2 hrs short luminescent afterglow time, and luminous brightness was weak etc., all these can not satisfy the requirement for practice use. In order to improve the brightness and afterglow time, radioactive luminescent materials were made, in which some radioactive elements such as CO,Ra,H₃ were added, although such elements can make the phosphor continuously give out light and the phosphor has once been used in air dashboard, clock fields etc., but due to the radioactive contamination and rather expensive price, the application of the phosphor was greatly confined.

The aluminate long afterglow luminescent material was invented at the beginning of the nineties, as stated in China patent application laid open No. CN1053807A and China patent No. ZL92110744.7, its luminescent brightness, long afterglow character and stability were obviously superior to the above sulphide series products, and it has already been used in the articles for daily use, low illumination indicator board, clock, etc.

However these phosphors still have bad anti-moisture character, and they have strict restriction over the raw material's purity and form, besides, the production cost was higher, as well as single luminescent color etc., therefore it also can not satisfy the requirement of usage very well.

In 1968, T. L. Barry published the research results of luminescent spectrum and excitation spectrum of Me₃ MgSi₂ O₈ :Eu²⁺ (Me=Ca, Sr and Ba) and Me₂ SiO₄ :Eu²⁺ (Me=Sr and Ba)(J. Electrochem. Soc. V115 No. 7, 733-738, 1968: V115 No. 11, 1181-1184, 1968); then T. L. Barry published the research result in luminescent and excitation spectrum of BaMg₂ Si₂ O₇ :Eu²⁺ (J. Electrochem. Soc. V117 No. 3, 381-385, 1970); Blasse, G etc. published fluorescence of Eu²⁺ activated silicates (Philips Res. Rep. (1968), 23 (2), 189-200) in 1968. However no report on silicate phosphor which having long afterglow property has been published.

SUMMARY OF THE INVENTION

In order to solve the above problem existed in the prior art, the invention provides a kind of series silicate long afterglow luminescent material that having various luminescent colors, wide scope spectrum, better anti-moisture property and nice stability as well as the long afterglow time and high afterglow brightness.

This invention provides a new type of series long afterglow luminescent material, it is a kind of long afterglow luminescent material which use silicate as main matrix, rare earth ions and other ions as activator, and add some compounds of B or P to make the improvement of long afterglow performance, thus blue, green, yellow etc. multiple colors long afterglow luminescent characters were gained in the silicate system.

The main chemical composition of long afterglow luminescent material in this invention can be expressed by the formula:

    aMO·bM'O·cSiO.sub.2 ·dR:Eu.sub.x,Ln.sub.y(1)

Wherein

M represents one or more elements selected from a group consisting of Sr(strontium), Ca(calcium), Ba(barium) and Zn(zinc);

M' represents one or more elements selected from a group consisting of Mg(magnesium), Cd(cadmium), and Be(beryllium);

R represents one or two components selected from B₂ O₃ (boric anhydride) and P₂ O₅ (di-phosphoruspentoxide);

Ln represents one or more elements selected from a group consisting of Nd(neodymiun), Dy(dysprosium), Ho(holmium), Tm(thulium), La(lanthanum), Pr(praseodymium), Tb(terbium), Ce(cerium), Mn(manganese), Bi(bismuth), Sn(tin), and Sb(antimony);

a, b, c, d, x and y are mole coefficients, wherein: 0.6≦a≦6, 0≦b≦5, 1≦c≦9, 0≦d≦0.7, 0.00001≦x≦0.2, and 0≦y≦0.3; these luminescent materials can give an emission spectrum between 420-650 nm when excited by the short wavelength light of 250-500 nm, its peak position is 450-580 nm, and the long afterglow luminescent colors are blue, bluish-green, green, greenish-yellow or yellow.

A preferred group of long afterglow luminescent materials according to this invention can be expressed by the main chemical composition formula (1), wherein M represents one or two elements selected from Sr and Ca; M' represents Mg;R represents one or two components selected from B₂ O₃ and P₂ O₅ ; Ln represents one or more elements selected from a group consisting of Nd, Dy, Ho, Bi and Sn, wherein 0.6≦a≦4, 0.6≦b≦4, 1≦c≦5, and 0≦d≦0.4. Preferable, the long afterglow luminescent material of this invention is characterized in that 0-40 mol % of the elements M and/or M' can be replaced by one or more elements selected from Ba, Zn, Cd and Be.

In a preferred group of long afterglow luminescent materials according to this invention, the main matrix compound of the phosphor is: M₂ MgSi₂ O₇ or M₃ MgSi₂ O₇ : Eu,Ln or M₃ MgSi₂ O₈ :Eu,Ln, wherein M represents Sr₁₋₂ Ca_(z), 0≦z≦1.

In the technique of making the long afterglow luminescent material of this invention, the compounds which containing the elements in the formula (1) are used as raw material, the mole proportion of elements in the raw material used to produce the luminescent material are as follows:

M: 0.6-6 R: 0-0.7 in terms of B₂ O₃ and P₂ O₅

M': 0-5 Eu: 0.00001-0.2

Si: 1-9 Ln:0-0.3

wherein

M represents one or more elements selected from a group consisting of Sr, Ca, Ba and Zn,;

M' represents one or more elements selected from a group consisting of Mg, Cd and Be;

R represents one or two elements selected from B and P;

Ln represents one or more elements selected from a group consisting of Nd, Dy, Ho, Tm, La, Pr, Tb, Ce, Mn, Bi, Sn and Sb;

Wherein M, M', Ln and Eu can be incorporated in the raw materials in the form of carbonate, sulphate, nitrate, phosphate, borate, acetate, oxalate, citrate, oxide, hydroxide or halogenide or the elements or their mixture; Si can be added in the form of SiO₂, silicic acid, silica gel or silicate; R can be added in the form of any compounds containing B or P, with the proviso that such compounds can form B₂ O₃ or P₂ O₅ in the subsequent sintering procedure;

In order to produce the desired phosphor, high temperature solid-phase reaction method is used, first weighted above raw materials according to mole proportion, then ground it into fine and mixed homogeneously by using dry-mixing method, wet-mixing method in with solvents e.g. alcohol, acetone, are added and evaporated after the mixing or chemical reaction sol;-gel process method; the mixture is placed in the crucible then sintered at a temperature between 1100˜1400° C. in furnace under a reducing atmosphere for about 2 to 50 hours depends on the oven's capacity and mixture's weight, for small amount mixture, it is usually fired for 2-5 hours, the reducing atmosphere is selected from H₂ (g), NH₃ (g), N₂ (g)+H₂ (g) and carbon powder, wherein g=gas.

In order to improve the phosphor's quality, small amount (0.15 wt % based on the total weight of raw material) of additives selected from the group consisting of the compounds NH₄ Cl, NH₄ F, CaF₂, SrF₂, Li₂ CO₃, CaSO₄, SrSO₄, SrHPO₄, and CaHPO₄ can be added into the raw material to participate in solid phase reaction. After sintering, the sintered mixture is milled and sifted into desired particle size phosphor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents the emission spectrum(a) and the excitation spectrum (b) of Sr₂ MgSi₂ O₇ :Eu phosphor

FIG. 2 represents the x-ray diffraction pattern of Sr₂ MgSi₂ O₇ :Eu phosphor

FIG. 3 represents the emission spectrum(a) and the excitation spectrum (b) of Sr₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 4 represents the afterglow characteristic curve of Sr₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 5 represents the emission spectrum(a) and the excitation spectrum(b) of Ca₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 6 represents the x-ray diffraction pattern of Ca₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 7 represents the afterglow characteristic curve of Ca₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 8 represents the emission spectrum(a) and the excitation spectrum(b) of (Sr₀.5 Ca₀.5)₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 9 represents the x-ray diffraction pattern of (Sr₀.5 Ca₀.5)₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 10 represents the afterglow characteristic curve of (Sr₀.5 Ca₀.5)₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 11 represents the emission spectrum(a) and the excitation spectrum(b) of (Sr₀.75 Ca₀.25)₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 12 represents the emission spectrum(a) and the excitation spectrum(b) of (Sr₀.25 Ca₀.75)₂ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 13 represents the emission spectrum(a) and the excitation spectrum(b) of Sr₃ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 14 represents the x-ray diffraction pattern of Sr₃ MgSi₂ O₇ :Eu,Dy phosphor

FIG. 15 represents the emission spectrum(a) and the excitation spectrum(b) of Ca₃ MgSi₂ O₈ :Eu,Dy phosphor

FIG. 16 represents the x-ray diffraction pattern of Ca₃ MgSi₂ O₈ :Eu,Dy phosphor

FIG. 17 represents the emission spectrum(a) and the excitation spectrum(b) of Ba₅ Si₈ O₂₁ :Eu,Dy phosphor

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The measurement of sample's luminescent afterglow in this invention is to put the sample in a 50 mm diameter, 5 mm deep disc, and keep it in dark room for more than 10 h, then took it out and put it under standard D65 light 10001× illuminance, after irradiated for 10 min use luminance meter measure its brightness changes with time. In the same time, excited the comparative sample under the same conditions, use comparative sample as 100 to count the sample's relative brightness value. For blue afterglow, the comparative sample is (CaSr)S:Bi; for yellow afterglow, the comparative sample is (ZnCd)S:Cu; and for green, bluish-green, greenish-yellow afterglow, the comparative sample is ZnS:Cu. Adopt x-ray diffraction method to define the phosphor's crystal structure and component, measured its x-ray diffraction value, and compared it with card value, so can define its main compound. Adopt fluorescent spectrophotometer to measure the phosphor's emission spectrum and excitation spectrum.

A lot of research work indicated that in the chemical composition formula, the different of element in M and M', results in the different colors of long afterglow, as well as the different of phosphor's main crystal structure; the change of a, b, and c value have some influences to the brightness, crystal structure and luminescent color; the different elements component in R and Ln and the change of d, x, and y coefficient value have obvious influence to the brightness, whereas have no obvious influence to the main crystal structure.

TABLE 1 shows a part of experimental results concerning the relationship between luminescent color and M, m',a,b.

TABLE 1 Experimental condition let c=2.5, d=0.1, R=B₂ O₃, x=0.005, y=0.04, Ln=Nd, select N₂ (90%)+H₂ (10%) as reducing atmosphere, synthetic temperature 1250-1320° C., sintering time 4 hrs.

                  TABLE 1                                                          ______________________________________                                         Experiment of luminescent color                                                    Ele-                                            Lu-                            ment                                            mi-                            co-                                             nes-                           ef-                                             cent                           fi-    M:                      M':              col-                       Ex  cient  a:    Sr   Ca   Ba  Zn  b:  Mg   Cd  Be  or                         ______________________________________                                         1                3    0                1            blue                       2                0    3                1            green                      3                2    0                1            blue                       4                0    2                1            yellow                     5                0.5  1.5              1            green-                                                                         ish-                                                                           yellow                     6                1.0  1.0              1            green                      7                1.5  0.5              1            bluish-                                                                        green                      8                1    0                2            blue                       9                0    1                2            yellow                     10               0.2  0.8              1.9  0.1     green-                                                                         ish-                                                                           yellow                     11               0.5  0.5              2            green                      12               0.7  0.3              1.9      0.1 bluish-                                                                        green                      13               1    0                3            blue                       14               0    1                3            yellow                     15               0.25 0.75             3.0          green-                                                                         ish-                                                                           yellow                     16               0.5  0.5              3.0          green                      17               0.75 0.25             3            blu-                                                                           ish-                                                                           yellow                     18               1    1.8  0.2         1            green-                                                                         ish-                                                                           yellow                     19               1.4  1.4      0.2     1            green                      20               2.0  1                1            blu-                                                                           ish-                                                                           green                      21               1.4  0.35             1.25         blu-                                                                           ish-                                                                           green                      22               1.2  0.3              1.5          blu-                                                                           ish-                                                                           green                      23               1.0  0.25             1.75         blu-                                                                           ish-                                                                           green                      24               0.875                                                                               0.875            1.25         green                      25               0.75 0.75             1.5          green                      26               0.625                                                                               0.625            1.75         green                      27               0.525                                                                               1.225            1.25         green-                                                                         ish-                                                                           yellow                     28               0.45 1.05             1.5          green-                                                                         ish-                                                                           yellow                     29               0.375                                                                               0.875            1.75         green-                                                                         ish-                                                                           yellow                     30               0.363                                                                               1.487            1.25         light                                                                          yellow                     31               0.225                                                                               1.275            1.5          light                                                                          yellow                     32               0.187                                                                               1.063            1.75         light                                                                          yellow                     ______________________________________                                    

When M represents Sr or represents Sr,Ca,Ba and Zn, wherein Sr is the main element, Ca, Ba, and Zn are secondary elements, M' represents Mg or represents Mg,Cd and Be, wherein Mg is the main element, Cd and Be are secondary elements, the synthetic phosphor can presents blue--bluish-green afterglow luminescence after irradiated by short wavelength light of 250-450 nm. Experiments indicate that the different value of a, b and c has certain influence to the phosphor's luminescent brightness and structure, when 0.6≦a≦4, 0.6≦b≦4 and 1≦c≦5, the phosphor presents brighter blue--bluish-green luminescent color, when 1.5≦a≦2, 0.6≦b≦2, and 1.5≦c≦2.5, according to the x-ray diffraction pattern, the main matrix compound of the phosphor is defined as Sr₂ MgSi₂ O₇ as well as its crystal structure, see FIG. 2; when exceed the above coefficient scope, there may appear Sr₂ MgSi₂ O₇ compound, but the more other compounds exist too; when 2.7≦a≦3.3, 0.8≦b≦1.2 and 1.7≦c≦2.3, the phosphor's main compound is Sr₃ MgSi₂ O₈, see FIG. 14.

When M represents Ca or represents Ca,Sr,Ba and Zn, wherein Ca is the main element, Sr, ba and Zn are secondary elements, M' represents Mg or represents Mg,Cd and Be, wherein Mg is the main element, Cd and Be are secondary elements, the synthetic phosphor can presents green-yellow afterglow luminescent color after irradiated by the short wavelength light of 250-500 nm. The same experiment indicates that the different value of a, b and c has certain influence to the phosphor's luminescent brightness and structure, when 0.6≦a≦4, 0.6≦b≦4, 1≦c≦5, the phosphor presents brighter green-yellow luminescence, when 1.5≦a≦2.4, 0.6≦b≦2, and 1.5≦c≦2.5, according to the x-ray diffraction pattern, the main matrix compound of the phosphor is defined as Ca₂ MgSi₂ O₇ as well as its crystal structure, see FIG. 6; when exceed the above coefficient scope, there may appear Ca₂ MgSi₂ O₇ compound, but the other compounds are more than the former; when 2.7≦a≦3.3, 0.8≦b≦1.2, and 1.7≦c≦2.3, the phosphor's main matrix compound is Ca₂ MgSi₂ O₈, see FIG. 16.

When M represents Sr and/or Ca, for easy to show, adopt formula Sr_(1-z) Ca_(z), wherein 0≦z≦1, or represent Sr_(1-z) Ca_(z), Ba and Zn, wherein Sr_(1-z) Ca_(z) are the main element, Ba and Zn are secondary elements, M' represents Mg or represents Mg, Cd and Be, wherein Mg is the main element, Cd and Be are secondary elements, with the change of z value, the synthetic phosphor presents blue--bluish-green--greenish-yellow--yellow the afterglow luminescence: when z=0, color is blue; z=1, it's green-yellow; 0<z<0.5, mainly is bluish-green--green color; 0.5<z<1, mainly is green-greenish-yellow color; z=0.5 or near it is green. Just the same, the different values of a, b and c have certain influence to the phosphor's luminescent brightness and structure, when 0.6≦a≦4, 0.6≦b≦4 and 1≦c≦5, the phosphor presents bluish-green, green and greenish-yellow afterglow luminescent color, when 1.5≦a≦2.4 0.6≦c≦2 and 1.5≦c≦2.5, analyze its diffraction pattern it is similar to that of Sr₂ MgSi₂ O₇ and Ca₂ MgSi₂ O₇, considering with the element's match, the phosphor's main matrix compound can be deduced as (Sr_(1-z) Ca_(z))₂ MgSi₂ O₇, see FIG. 9; when the above coefficients scope are exceeded, the compound of (Sr_(1-z) Ca_(z))₂ MgSi₂ O₇ can be appeared, but there are more other components.

Refer to the luminescent material's formula in Luminescence, when the crystal structure of phosphor have not yet been defined, it can be expressed by the main component of the phosphor, that is expressed by chemical composition formula; when the main compound and the crystal structure of the phosphor is defined, it should be expressed by chemical formula in this invention.

According to the compound and crystal structure of the above phosphor in this invention, the main chemical formula of this phosphor is: M₂ MgSi₂ O₇ :Eu, Ln or M₃ MgSi₂ O₈ :Eu Ln, wherein M presents Sr_(1-z) Ca₂ 0≦z≦1.

When M represents Ba, 4≦a≦6, b=0 and 6≦c≦9, the phosphor presents light green afterglow, according to x-ray diffraction pattern its main compound is defined as Ba₅ Si₈ O₂₁, so the main chemical formula of this phosphor is Ba₅ Si₈ O₂₁ :Eu,Ln.

When M represents Zn, 1≦a≦3, b=0 and 0.7≦c≦1.5, the phosphor presents light green afterglow, according to x-ray diffraction pattern its main compound is defined as Zn₂ SiO₄, so the main chemical formula of this phosphor is Zn₂ SiO₄ :Eu,Ln.

When M represents Sr_(1-z) Ca_(z) 0≦z≦1, M' represents Mg, where 0-40% mol M and/or M' can be replaced by one or more elements selected from a group consisting of Ba, Zn Cd and Be, the phosphor has long afterglow property, especially when 5-20% mol M and/or M' replaced by one or two of Ba and Cd, the phosphor have good luminescent performance.

In chemical composition formula, without R and/or Ln element (that is when d and/or y is zero), the synthetic phosphor can also give out afterglow. If R and/or Ln exist in the phosphor, its luminescent afterglow intensity has been strengthened obviously, certainly the mole coefficient d and y may affect the afterglow luminescent intensity, adding different elements of Ln causes different luminescent intensity, two or more elements' adding will be even better than that of single element in luminescent effect.

When y=0, the phosphor's chemical composition formula is aMO·bM'O·cSiO₂ ·dR:Eu_(x), Eu is the activator, its emission spectrum is characterized by Eu²⁺, that means Eu is the main activator, the afterglow luminescent intensity changes with x value, the suitable scope of x is: 0.00001≦x≦0.2.

When y>0, Ln exists in the phosphor, the experiment indicate that when one or more elements of Nd, Dy, Ho, Tm, La, Pr, Tb, Ce, Mn, Bi, Sn and Sb are doped, it will have certain enhance in phosphor's luminescent intensity, especially obvious effect can be seen in Nd,Dy,Ho,Bi and Sn, experiment indicate that when 0>y≦0.3, it has obvious enhancement function to the phosphor, whose afterglow luminescent intensity are much higher and the decay time are much longer than that of without Ln, see experiment in TABLE 2-10, according to the Luminescence theory, it can act as co-activator function.

When d=0, the phosphor's chemical composition formula is aMO·bM'O·cSiO₂ ·dR:Eu_(x),Ln_(y), this phosphor presents certain long afterglow effect the afterglow luminescent intensity changes with x and y value.

When d>0, the adding of R component can obviously improve the phosphor's long afterglow luminescent intensity compared with that of d=0, the R component of the phosphor can be the compounds of B or p, i.e. B₂ O₃, H₃ BO₃, P₂ O₅, H₃ PO₄, (NH₄)₂ HPO₄, NH₄ H₂ PO₄ etc., adding of these components can improve the phosphor's long afterglow luminescent intensity, reduce the phosphor's synthetic temperature, improve the phosphor's synthetic quality, and loosened the powder of synthetic phosphor, increase the produce rate.

The influence of R component to the phosphor's luminescent property, see TABLE 2.

TABLE 2 Select bluish-green phosphor in this experiment, let M=Sr₀.75 Ca₀.25, M'=Mg, R=B₂ O₃ and/or P₂ O₅, Ln=Dy, a=1.5, b=1.5, c=2.5, x=0.01, y=0.08, NH₃ (g) as reducing atmosphere, and synthetic temperature at 1280° C.

                                      TABLE 2                                      __________________________________________________________________________     The R and Ln component function experiment                                                                    Relative afterglow                                                             intensity                                       Ex                                                                               Chemical composition formula 10°                                                                          60°                                 __________________________________________________________________________     1 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :Eu.sub.0.01                                              40.1 102                                        2 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :0.1B.sub.2 O.sub.3          :Eu.sub.0.01                 114  176                                        3 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :0.5P.sub.2 O.sub.3          :Eu.sub.0.01                 94.6 137                                        4 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :0.1B.sub.2 O.sub.3.0.       05P.sub.2 O.sub.5 :Eu.sub.0.01                                                                              121  182                                        5 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :Eu.sub.0.01 Dy.sub.0.       08                           772  1540                                       6 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :0.1B.sub.2 O.sub.3          :Eu.sub.0.03 Dy.sub.0.08     2541 4808                                       7 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :0.05P.sub.2 O.sub.5         :Eu.sub.0.03 Dy.sub.0.08     1724 3946                                       8 1.5(Sr.sub.0.75 Ca.sub.0.25)O.1.5MgO.2.5SiO.sub.2 :0.1B.sub.2 O.sub.3.0.       05P.sub.2 O.sub.5 :Eu.sub.0.01 Dy.sub.0.08                                                                  2638 4972                                       __________________________________________________________________________

The influence of R's amount to the phosphor's luminescent property, show in TABLE 3. TABLE 3 select blue and green phosphor, in experiment 1-8, let M=Sr, M'=Mg, a=2, b=1, c=2, R=B₂ O₃, x=0.004.

Experiment 9-14 is green phosphor, wherein M=Sr₀.5 Ca₀.5, M'=Mg, a=2, b=1, c=2.3, R=P₂ O₅, Ln=Dy, x=0.004, y=0.01.

                                      TABLE 3                                      __________________________________________________________________________     The effect of R component experiment:                                                                             Relative                                                              R        afterglow                                                                               synthesizing                                                 (raw     intensity                                                                               temperature                        Ex.                                                                               Chemical composition formula                                                                          material)                                                                            d  10'  60' (C.°)                       __________________________________________________________________________     1  2SrO.MgO.2SiO.sub.2 :Eu.sub.0.004                                                                     0     0  37.4 100 1350                               2  2SrO.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3 :Eu.sub.0.004                                                 2H.sub.3 BO.sub.3                                                                    0.01                                                                              78.7 115.4                                                                              1340                               3  2SrO.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3 :Eu.sub.0.004                                                 2H.sub.3 BO.sub.3                                                                    0.05                                                                              134.8                                                                               169.2                                                                              1330                               4  2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3 :Eu.sub.0.004                                                  2H.sub.3 BO.sub.3                                                                    0.1                                                                               132.4                                                                               158.5                                                                              1320                               5  2SrO.MgO.2SiO.sub.2.0.2B.sub.2 O.sub.3 :Eu.sub.0.004                                                  2H.sub.3 BO.sub.3                                                                    0.2                                                                               109.2                                                                               127 1310                               6  2SrO.MgO.2SiO.sub.2.0.3B.sub.2 O.sub.3 :Eu.sub.0.004                                                  2H.sub.3 BO.sub.3                                                                    0.3                                                                               94.5 102 1280                               7  2SrO.MgO.2SiO.sub.2.0.5B.sub.2 O.sub.3 :Eu.sub.0.004                                                  2H.sub.3 BO.sub.3                                                                    0.5                                                                               73.4 96.4                                                                               1230                               8  2SrO.MgO.2SiO.sub.2.0.7B.sub.2 O.sub.3 :Eu.sub.0.004                                                  2H.sub.3 BO.sub.3                                                                    0.7                                                                               42.1 74.2                                                                               1150                               9  2(Sr.sub.0.3 Ca.sub.0.3)O.MgO.2.3SiO.sub.2 :Eu.sub.0.004 Dy.sub.0.01                                  0     0  482.4                                                                               1263.2                                                                             1350                               10 2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2.3SiO.sub.2.0.05P.sub.2 O.sub.5                 :Eu.sub.0.004 Dy.sub.0.01                                                                             2NH.sub.4 H.sub.2 PO.sub.4                                                           0.05                                                                              613  1804                                                                               1340                               11 2(Sr.sub.0.3 Ca.sub.0.5)O.MgO.2.3SiO.sub.2.0.1P.sub.2 O.sub.5 :Eu.sub.0        .004 Dy.sub.0.01       2NH.sub.4 H.sub.2 PO.sub.4                                                           0.1                                                                               1034 2542                                                                               1320                               12 2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2.3SiO.sub.2.0.2P.sub.2 O.sub.5 :Eu.sub.0        .004 Dy.sub.0.01       2NH.sub.4 H.sub.2 PO.sub.4                                                           0.2                                                                               807  2326                                                                               1310                               13 2(Sr.sub.0.3 Ca.sub.0.5)O.MgO.2.3SiO.sub.2.0.3P.sub.2 O.sub.5 :Eu.sub.0        .004 Dy.sub.0.01       2NH.sub.4 H.sub.2 PO.sub.4                                                           0.3                                                                               721  1702                                                                               1250                               14 2(Sr.sub.0.3 Ca.sub.0.5)O.MgO.2.3SiO.sub.2.0.5P.sub.2 O.sub.5 :Eu.sub.0        .004 Dy.sub.0.01       2NH.sub.4 H.sub.2 PO.sub.4                                                           0.5                                                                               501  1271                                                                               1200                               __________________________________________________________________________

Experiment indicates when 0≦d≦0.7, the phosphor's luminescent intensity can be influenced, the amount of R(d) at 0<d≦0.4 is better. The exist of R component, analyzed from phosphor's x-ray diffraction pattern, have no obvious influence on the above phosphor's crystal structure and compound, its main compound is silicate component, however, B and P elements existed in phosphor are defined by spectrometric analysis, that means the phosphor contains B and P components, according tis chemical composition, marked as B₂ O₃ and P₂ O₅.

A part of the long afterglow luminescent materials in this invention is described as follows:

(1) Blue long afterglow luminescent material

When M=Sr, M'=Mg, R=B₂ O₃, a=2, b=1, c=2, D=0.1, the phosphor's chemical composition formula is: 2SrO--MgO--2SiO₂₋₋₀.1 B₂ O₃ :Eu_(x) Ln_(y), change the value of x, the elements of Ln and the value of y, the experiment results shown in TABLE 4.

                  TABLE 4                                                          ______________________________________                                                                        Relative                                        Ex-                            afterglow                                       peri-                          intensity                                       ment   Chemical composition formula                                                                           10'    60'                                      ______________________________________                                         1-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.0001                                                   67     114                                      1-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.0004                                                   81     122                                      1-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.001                                                    124    143                                      1-4    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004                                                    136    178                                      1-5    2SrO.MgO.2SiO.sub.2 -0.1B.sub.2 O.sub.3.Eu.sub.0.001                                                   130    167                                      1-6    2SrO.MgO.2SiO.sub.2 -0.1B.sub.2 O.sub.3.Eu.sub.0.01                                                    91     121                                      1-7    2SrO.MgO.2SiO.sub.2 -0.1B.sub.2 O.sub.3.Eu.sub.0.2                                                     80     102                                      2-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.001                                       621    734                                      2-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.003                                       884    896                                      2-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.01                                        1130   1175                                     2-4    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.04                                        1527   1847                                     2-5    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.1                                         862    859                                      2-6    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.5                                         645    692                                      3-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.0005                                      592    913                                      3-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.004                                       927    1754                                     3-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.01                                        1108   2100                                     3-4    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.04                                        1658   3947                                     3-5    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.08                                        1421   3136                                     3-6    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.15                                        1215   2306                                     3-7    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.3                                         823    1214                                     4-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ho.sub.0.0004                                      827    1512                                     4-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ho.sub.0.001                                       1014   1894                                     4-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ho.sub.0.05                                        1472   2246                                     4-4    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ho.sub.0.1                                         1034   1675                                     5-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tm.sub.0.001                                       289    310                                      5-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tm.sub.0.05                                        378    420                                      5-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tm.sub.0.1                                         384    456                                      6-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 La.sub.0.001                                       204    189                                      6-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 La.sub.0.005                                       235    267                                      6-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 La.sub.0.02                                        269    317                                      7-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Pr.sub.0.001                                       275    292                                      7-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Pr.sub.0.004                                       254    264                                      7-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Pr.sub.0.02                                        250    253                                      8-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tb.sub.0.001                                       224    267                                      8-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tb.sub.0.004                                       284    368                                      8-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tb.sub.0.02                                        230    276                                      9-1    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ca.sub.0.0017                                      278    367                                      9-2    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ca.sub.0.007                                       238    262                                      9-3    2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ca.sub.0.0027                                      224    237                                      10-1   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Mn.sub.0.001                                       264    290                                      10-2   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Mn.sub.0.005                                       273    287                                      10-3   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Mn.sub.0.02                                        232    264                                      11-1   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Bi.sub.0.001                                       254    347                                      11-2   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Bi.sub.0.005                                       314    472                                      11-3   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Bi.sub.0.02                                        421    564                                      12-1   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Sb.sub.0.0016                                      195    227                                      12-2   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Sb.sub.0.006                                       184    215                                      12-3   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Mn.sub.0.025                                       147    169                                      13-1   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Sn.sub.0.001                                       124    138                                      13-2   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Sn.sub.0.005                                       278    367                                      13-3   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Sn.sub.0.02                                        167    236                                      14-1   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.02                Dy.sub.0.01             1831   3150                                     15-1   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.02                Sn.sub.0.01             1672   2804                                     16-1   2SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.02                Bi.sub.0.01             1837   4356                                     Compar-                                                                               Zn:S:Cu                 100    100                                      ative                                                                          sample                                                                         ______________________________________                                    

The experimental phosphor shown in TABLE 4 can display blue afterglow luminescence after irradiated under sun light, fluorescent lamp or ultraviolet lamp, when excited under 365 nm ultraviolet light, it can give 420-550 nm broad band emission spectrum, with peak position near 469 nm; its excitation spectrum is 250-450 nm broad band spectrum, when monitoring at 469 nm, indicate this phosphor has strong absorbing ability to short wavelength light, its main matrix compound is defined as Sr₂ MgSi₂ O₇ through x-ray diffraction pattern, the peak position of spectrum can exert certain shift for the different adding component. FIG. 1 (a), (b) and FIG. 2 are emission spectrum, excitation spectrum and x-ray diffraction pattern of the experimental phosphor 1-4 respectively, whose emission spectrum peak position is 469 nm; FIG. 3(a), (b) are emission spectrum and excitation spectrum of the experimental phosphor 3-4, its emission spectrum peak position is 470 nm.

1. If y=0 in the chemical composition formula, that means no Ln ion exist, the amount of Eu(x) added may have certain influence to afterglow intensity, shown as experiment 1-1˜7 in TABLE 4. Compared with comparative sample (CaSr)S:Bi, this phosphor presents certain long afterglow luminescent effect. Further experiment indicates that when the Eu's amount x is less than 0.00001 mol or more than 0.2 mol. its luminescent intensity is weak, so 0.00001≦x≦0.2 is defined.

2. If x=0.004, Ln=Nd, the afterglow intensity corresponding to the changes of the amount of Nd(y) added, see experiment 2-1˜6 in TABLE 4, 0.00001≦y≦0.3 are suitable for the amount of Nd(y) added, it can be seen that afterglow intensity is obviously stronger than that of experiment 1-1˜7, this indicate that the adding of Nd can strengthen the phosphor's luminescent performance. Draw a log--log afterglow afterglow characteristic curve concerning the phosphor's luminescent afterglow varies with the decay time, this curve is almost a straight line, its decay time can prolong to more than 20 hrs when afterglow brightness reach the eye's lowest visual luminosity 0.32 mcd/m².

3. If x=0.004, Ln=Nd, the afterglow intensity corresponding to the changes of the amount of Dy(y) added, see experiment 3-1˜7 in TABLE 1, 0.00001≦y≦0.3 are suitable for the amount of Dy(y) added, it can be seen that afterglow intensity is obviously stronger than that of experiment 1-1˜7, this indicates that the adding of Dy strengthened the phosphor's luminescent performance. Draw a log--log afterglow afterglow characteristic curve concerning the phosphor's luminescent afterglow varies with the decay time, this curve was almost a straight line, see FIG. 4, its decay time can prolong for more than 35 hrs by eye's lowest visual luminosity.

4. If x=0.004, Ln is Ho, Tm, La, Pr, Tb, Ce, Mn, Bi, Sb, Sn and double elements Nd, Dy; Nd, Sn; and Dy, Bi respectively, its afterglow effect that corresponding the amount of Ly(y) added, see experiment 4˜16 in TABLE 4.

From the above results, it can be seen that these phosphor's luminescent afterglow effect are obviously superior to that of the comparative phosphor. Especially the adding of Nd, Dy, Ho, Bi, Sn makes the effect even better. According to the crystal structure and main compound of the above phosphor, the blue series phosphor's chemical formula is Sr₂ MgSi₂ O₇ :Eu,Ln.

(2) Yellow long afterglow luminescent material

When M=Ca, M'=Mg, R=B₂ O₃, a=2, b=1, c=2, d=0.15, the phosphor's chemical composition formula is: 2CaO·MgO·2SiO₂ ·0.15B₂ O₃ :Eu_(x),Ln_(y), change the value of x, the elements of Ln, and the value of y, its experimental results shown in TABLE 5.

                  TABLE 5                                                          ______________________________________                                                                        Relative                                        Ex-                            afterglow                                       peri-                          intensity                                       ment   Chemical composition formula                                                                           10'    60'                                      ______________________________________                                         1-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.0001                                                   127    217                                      1-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004                                                    201    404                                      1-3    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.001                                                    238    417                                      1-4    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004                                                    223    389                                      1-5    2CaO.MgO.2SiO.sub.2 -0.1B.sub.2 O.sub.3.Eu.sub.0.001                                                   152    345                                      1-6    2CaO.MgO.2SiO.sub.2 -0.1B.sub.2 O.sub.3.Eu.sub.0.01                                                    56     127                                      1-7    2CaO.MgO.2SiO.sub.2 -0.1B.sub.2 O.sub.3.Eu.sub.0.2                                                     45     87                                       2-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3 Eu.sub.0.004 Dy.sub.0.0005                                      387    1071                                     2-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.01                                        832    1324                                     2-3    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.05                                        914    1451                                     2-4    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.15                                        597    921                                      3-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.0002                                      512    714                                      3-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Nd.sub.0.01                                        490    837                                      4-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ho.sub.0.01                                        482    694                                      4-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ho.sub.0.05                                        531    728                                      5-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tm.sub.0.01                                        417    623                                      5-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Tm.sub.0.05                                        465    704                                      6-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ce.sub.0.0015                                      317    572                                      6-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Ce.sub.0.05                                        354    643                                      7-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Sn.sub.0.001                                       397    845                                      7-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Sn.sub.0.004                                       492    897                                      8-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Bi.sub.0.001                                       426    823                                      8-2    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Bi.sub.0.04                                        549    864                                      9-1    2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.02                Nd.sub.0.01             965    1534                                     10-1   2CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3.Eu.sub.0.004 Dy.sub.0.02                Bi.sub.0.01             873    1424                                     Compar-                                                                               (ZnCd)S:Cu              100    100                                      ative                                                                          sample                                                                         ______________________________________                                    

The experimental phosphor can display yellow afterglow luminescence after irradiated under sunlight, fluorescent lamp or ultraviolet lamp; when excited under 365 nm ultraviolet light the phosphor can give 420-650 nm wide band emission spectrum, peak value at 535 nm; its excitation spectrum is broad band spectrum between 250-500 nm when monitoring at 535 nm, indicates this phosphor has strong absorbing ability to short wavelength light; its main matrix compound is defined as Ca₂ MgSi₂ O₇ ; Due to the different adding components, its spectrum peak position can be shifted certain displacement. FIG. 5(a), (b) and FIG. 6 are the emission spectrum, excitation spectrum and x-ray diffraction pattern of the experimental phosphor 2-3 respectively, its emission spectrum peak position is at 535 nm.

1. If y=0 in the chemical composition formula, the amount of Eu(x) added can has certain influence to the afterglow intensity, see the experiment 1-1˜7 in TABLE 5.

2. If x=0.004, Ln=Dy, the relationship between the amount of Dy(y) added and the afterglow effect shown in TABLE 5 of experiment 2-1˜4, it can be seen that the adding of Dy enhance the phosphor's luminescent performance, experiment indicate that 0.0001≦y≦0.2 are better for the amount of Dy added, FIG. 7 is log--log characteristic curve of experiment 2-3 phosphor's luminescent afterglow changes with the decay time.

3. If x=0.004, Ln is Nd, Ho, Tm, Ce, Sn, Bi and double Dy, Nd and Dy, Bi respectively, the relationship between the adding amount and afterglow effect are superior to that of comparative sample. According to the above phosphor's main compound, the chemical formula of the yellow series phosphor is Ca₂ MgSi₂ O₇ :Eu,Ln.

(3) Green long afterglow luminescent material

When M=Sr₀.5 Ca₀.5, m'=Mg, R=B₂ O₃, a=2, b=1, c=2, d=0.05, the chemical composition formula is: 2(Sr₀.5 Ca₀.5)O·MgO·2SiO₂ ·0.05B₂ O₃ : Eu_(x) Ln_(y), change the value of x, the elements of Ln, and the value of y, its experimental results shown in TABLE 6.

                                      TABLE 6                                      __________________________________________________________________________                                   Relative afterglow                                                             intensity                                        Experiment                                                                           Chemical composition formula                                                                           10'  60'                                         __________________________________________________________________________     1-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005           89.5 226.3                                       1-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.001           105.3                                                                               247.4                                       1-3   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.004           89.5 323                                         1-4   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.01            52.6 215                                         1-5   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.02            42.1 110.5                                       1-6   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.1             21   57.9                                        2-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Dy.sub.0.0005                                                                            562  1515                                        2-2   2(Sr.sub.0.3 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Dy.sub.0.004                                                                             1237 3333                                        2-3   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Dy.sub.0.008                                                                             1206 3158                                        2-4   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Dy.sub.0.04                                                                              1246 3421                                        2-5   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Dy.sub.0.08                                                                              1219 3591                                        3-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Nd.sub.0.0064                                                                            1127 2815                                        3-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Nd.sub.0.008                                                                             1212 3032                                        3-3   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Nd.sub.0.16                                                                              1146 3012                                        4-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Ho.sub.0.01                                                                              472  1324                                        4-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Ho.sub.0.05                                                                              534  1427                                        5-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Tm.sub.0.01                                                                              567  1624                                        5-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Tm.sub.0.05                                                                              621  1735                                        6-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Ce.sub.0.0015                                                                            116  184                                         6-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Ce.sub.0.006                                                                             95   174                                         6-3   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Ce.sub.0.02                                                                              116  216                                         7-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Sn.sub.0.001                                                                             118  267                                         7-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Sn.sub.0.005                                                                             234  349                                         7-3   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Sn.sub.0.02                                                                              121  254                                         8-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Tb.sub.0.0013                                                                            89.5 231.6                                       8-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Tb.sub.0.0053                                                                            94.7 242                                         8-3   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Tb.sub.0.021                                                                             31.6 368                                         9-1   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Pr.sub.0.0015                                                                            52.6 136.8                                       9-2   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Pr.sub.0.006                                                                             73.7 194.7                                       9-3   2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Pr.sub.0.023                                                                             89.5 226.3                                       10-1  2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Bi.sub.0.001                                                                             154  317                                         10-2  2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0005 Bi.sub.0.005                                                                              282  431                                         10-3  2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Bi.sub.0.02                                                                              297  442                                         11-1  2(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.3.0.05B.sub.2 O.sub.3                   :Eu.sub.0.005 Dy.sub.0.02 Bi.sub.0.01                                                                  2042 4127                                        Comparative                                                                          ZnS:Cu                  100  100                                         sample                                                                         __________________________________________________________________________

The experimental phosphor in TABLE 6 can display green afterglow luminescence after irradiated under sunlight, fluorescent lamp or ultraviolet lamp; when excited under 365 nm ultraviolet light, the phosphor can give 430-600 nm broad band emission spectrum, peak position near 500 nm; its excitation spectrum is broad band spectrum between 250-460 nm, when monitoring at 500 nm, indicated that this phosphor has stronger absorption ability for the short wave light; analyzed from x-ray diffraction patterns, it can be seen that this phosphor diffraction patterns is similar to that of Sr₂ MgSi₂ O₇ and Ca₂ MgSi₂ O₇, concerning the mole proportion of Sr and Ca, the main matrix compound (Sr₀.5 Ca₀.5)₂ MgSi₂ O₇ can be deduced. For different addings, its peak position of spectrum can be shifted certain. FIG. 8(a), (b) and FIG. 9 are emission spectrum, excitation spectrum and x-ray diffraction pattern of experimental phosphor2-5 respectively, its emission spectrum peak position is 500 nm.

1. If y=0 in the chemical composition formula, the relationship between the amount of Eu(x) added and afterglow intensity, see experiment 1-1˜6 in TABLE 6.

2. If x=0.005, Ln=Dy, the relationship between the amount of Dy(y) and afterglow effect, see experiment 2-1˜6 in TABLE 6. IT can be seen that this phosphor has obviously strengthened in afterglow intensity compared with the phosphor of experiment 1-1˜6. FIG. 10 is the log--log characteristic curve concerning luminescent afterglow of phosphor in experiment 2-5 varies with the decay time, it indicates that the decay time can prolong to more than 50 hrs when afterglow brightness reach the eye's lowest visual luminosity 0.32 mcd/m².

3. If x=0.005, Ln=Nd, the relationship between the amount of Nd(y) added and the afterglow effect, see experiment 3-1˜3 in TABLE 6, it can be seen that afterglow intensity is higher and decay time is longer.

4. If x=0.005, Ln is Ho, Tm, Ce, Sn, Tb, Pr and Bi respectively, the influence of its adding amount to the afterglow intensity, see experiment 4-10 in TABLE 6.

5. If x=0.005, Ln=Dy and Bi, if Dy and Bi are both added in the same time, then obvious enhancement of luminescent afterglow intensity can be seen, see experiment 11 in TABLE 6.

According to the main compound of above phosphor, the chemical formula of the green series phosphor is: (Sr₀.5 C₀.5)₂ MgSi₂ O₇ :Eu,Ln.

(4) Bluish-green to greenish-yellow long afterglow luminescent material s

When M=Sr_(1-z) Ca_(z), M'=Mg, R=B₂ O₃, a=2, b=1, c=2, d=0.1, the phosphor's chemical composition formula is:

2(Sr_(1-z) Ca_(z))O·MgO·2SiO₂ ·0.1B₂ O₃ :Eu_(x),Ln_(y), 0≦z≦1, the phosphors' afterglow colors change from blue to yellow the the z value, when z=0, the color is blue; z=1, which is yellow; z=0.5, which is green. The phosphors' luminescent colors present the change from blue to green then yellow with the change of z value from 0 to 1, that means to change the proportion of Sr and Ca.

1. As shown in TABLE 7, test the influence of the change of the proportion Sr and Ca in 2(Sr_(1-z) Ca_(z))O·MgO·2SiO₂ ·0.1B₂ O₃ :Eu₀.004,Dy₀.02, to the emission spectrum peak position, it can be seen that the emission spectrum peak position changed from 469 nm to 535 nm varies as the z value changes from 0 to 1, this cause the luminescent color presents the change of blue, bluish-green, green, greenish-yellow and yellow, see TABLE 7.

                                      TABLE 7                                      __________________________________________________________________________     Z    0  0.1                                                                               0.2                                                                               0.3                                                                               0.4                                                                               0.5                                                                               0.6                                                                               0.7                                                                               0.8                                                                               0.9                                                                               1                                           __________________________________________________________________________     Sr   Sr Sr.sub.0.9                                                                        Sr.sub.0.8                                                                        Sr.sub.0.7                                                                        Sr.sub.0.6                                                                        Sr.sub.0.5                                                                        Sr.sub.0.4                                                                        Sr.sub.0.3                                                                        Sr.sub.0.2                                                                        Sr.sub.0.1                                                                        0                                           Ca   0  Ca.sub.0.1                                                                        Ca.sub.0.2                                                                        Ca.sub.0.3                                                                        Ca.sub.0.4                                                                        Ca.sub.0.5                                                                        Ca.sub.0.6                                                                        Ca.sub.0.7                                                                        Ca.sub.0.8                                                                        Ca.sub.0.9                                                                        Ca                                          Emission                                                                            469                                                                               473                                                                               482                                                                               485                                                                               496                                                                               500                                                                               505                                                                               509                                                                               517                                                                               532                                                                               535                                         spectra                                                                        peak, nm                                                                       __________________________________________________________________________

2. When z=0.25, select chemical composition formula 2(Sr₀.75 Ca₀.25)O·MgO·2SiO₂ ·0.1B₂ O₃ :Eu₀.004,Ln₀.02 to do experiment, shown as experiment 1˜6 in TABLE 8, the phosphors present bluish-green long afterglow luminescence and the adding of Ln ion can obviously strengthen its luminescent intensity as shown from experiment 2 in TABLE 8, there is a sharp difference compared with the comparative sample, a very strong bluish-green afterglow luminescence can be presented, and its emission spectrum, excitation spectrum are shown in FIG. 11(a),(b).

3. When z=0.75, select chemical composition formula 2(Sr₀.75 Ca₀.75)O·MgO·2SiO₂ ·0.1B₂ O₃ :Eu₀.004,Ln₀.02 as seen in experiment 7-12 of TABLE 8, the phosphors present greenish-yellow long afterglow luminescence, and the adding of Ln ion can obviously strengthen its luminescent intensity, which can be seen from experiment 8 in TABLE 8, there in an obvious enhancement compared with the comparative sample, its emission spectrum, excitation spectrum are shown FIG. 12(a),(b).

                                      TABLE 8                                      __________________________________________________________________________                              Relative afterglow                                                             intensity                                                                               Luminescent                                  Ex.                                                                               Chemical composition formula                                                                         10'  60' color                                        __________________________________________________________________________     1  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01          121  162 bluish-green                                 2  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Dy.sub.0.02                                                                             1758 3874                                                                               bluish-green                                 3  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Nd.sub.0.02                                                                             1121 1671                                                                               bluish-green                                 4  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Ho.sub.0.02                                                                             1023 1642                                                                               bluish-green                                 5  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Sn.sub.0.02                                                                             267  342 bluish-green                                 6  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Bi.sub.0.02                                                                             323  407 bluish-green                                 7  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01          171  303 greenish-yellow                              8  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Dy.sub.0.02                                                                             617  1247                                                                               greenish-yellow                              9  2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Nd.sub.0.02                                                                             517  928 greenish-yellow                              10 2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Ho.sub.0.02                                                                             361  808 greenish-yellow                              11 2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Sn.sub.0.02                                                                             231  431 greenish-yellow                              12 2(Sr.sub.0.75 Ca.sub.0.25)O.MgO.2SiO.sub.2.0.01B.sub.2 O.sub.3                 :Eu.sub.0.01 Bi.sub.0.02                                                                             272  489 greenish-yellow                              __________________________________________________________________________

(5) Other long afterglow luminescent materials

1. In the chemical composition formula, when M=Sr_(1-z) Ca_(z), wherein 0≦z≦1, M'=Mg, R=B₂ O₃, a=3, b=1, c=2, d=0.1, that means the formula is 3MO·MgO·2SiO₂ ·0.1B₂ O₃ :Eu_(x),Ln_(y), the phosphors display long luminescence from blue to greenish-yellow.

In TABLE 9, M=Sr, Ln=Dy or Nd was selected in experiment 1, the phosphors display blue long afterglow. The emission spectrum, excitation spectrum and x-ray diffraction pattern of 3SrO·MgO·2SiO₂ ·0.1B₂ O₃ :Eu₀.004,Dy₀.02 phosphor are shown in FIG. 13(a),(b) and FIG. 14 respectively. The peak of the emission spectrum is 462 nm. The dominant compound is Sr₃ MgSi₂ O₈, and the secondary is Sr₂ MgSi₂ O₇, The chemical formula of the phosphor Sr₃ MgSi₂ O₈ :Eu,Ln is defined.

In TABLE 9, M=Ca, Ln=Dy or Nd was selected in the experiment 2, the phosphors display light green long afterglow. The emission spectrum, excitation spectrum and x-ray diffraction pattern of the 3CaO·MgO 2SiO₂ :Eu₀.04,Dy₀.02 phosphor are shown in FIG. 15(a), (b) and FIG. 16 respectively and the peak of the emission spectrum is 475 nm. The dominant compound is Ca₃ MgSi₂ O₈, and the secondary is Ca₃ MgSi₂ O₇.

When M=Sr₀.5 Ca₀.5,Ln=Dy or Nd, the phosphors display bluish-green afterglow. The long afterglow property of them is shown in

the experiment 3-1˜2 of TABLE 9.

                                      TABLE 9                                      __________________________________________________________________________                                 Relative afterglow                                                             intensity                                                                               Luminescent                               Experiment                                                                           Chemical composition formula                                                                         10'  60' color                                     __________________________________________________________________________     1-1   3SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3 :Eu.sub.0.004 Nd.sub.0.02                                     211  489 blue                                      1-2   3SrO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3 :Eu.sub.0.004 Dy.sub.0.02                                     300  579 blue                                      2-1   3CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3 :Eu.sub.0.004 Nd.sub.0.02                                     31.4 56.1                                                                               light green                               2-2   3CaO.MgO.2SiO.sub.2.0.1B.sub.2 O.sub.3 :Eu.sub.0.004 Dy.sub.0.02                                     67.1 146 light green                               3-1   3(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2 :0.1B.sub.2 O.sub.3                   :Eu.sub.0.004 Dy.sub.0.02                                                                            173  345 bluish-green                              3-2   3(Sr.sub.0.5 Ca.sub.0.5)O.MgO.2SiO.sub.2 :0.1B.sub.2 O.sub.3                   :Eu.sub.0.004 Nd.sub.0.02                                                                            91   183 bluish-green                              Comparative                                                                          (CaSr)S:Bi            100  100                                           samples                                                                              ZnS:Cu                100  100                                           __________________________________________________________________________

2. In the chemical composition formula, when M is Sr_(1-z) Ca_(z), where 0≦z≦1, M' is Mg, 0-40% mol of M and/or M' can be partly taken the place by one or more elements from a group consisting of Ba, Zn, Cd, and Be, then the colors of the afterglow are blue, green, yellow etc.

The afterglow colors of the phosphors, in which M mainly consists of Sr, are from blue to blue-green, that is shown in the experiment of 1-1˜4 of TABLE 10, the long afterglow property of them is compared with (CaSr)S:Bi; if M mainly consists of Ca or Sr and Ca, the afterlow colors of the phosphors are from green to yellow, that is indicated in the experiment 2-1˜4 and 3-1˜2 of TABLE 10. The long afterglow property of them is compared with (ZnCd)S:Cu and ZnS:Cu respectively. It is obvious that the long afterglow property of these phosphor is much more superior than that of the comparative samples.

                                      TABLE 10                                     __________________________________________________________________________                                     Relative afterglow                                                             intensity                                      Experiment                                                                            Chemical composition formula                                                                            10'  60'                                       __________________________________________________________________________     1-1    2(Sr.sub.0.9 Zn.sub.0.1)O.MgO.2SiO.sub.2 0.1B.sub.2 O.sub.3                    :Eu.sub.0.004 Dy.sub.0.02                                                                               976  1793                                      1-2    2SrO.(Mg.sub.0.9 Zn.sub.0.1)O.2SiO.sub.2 0.1B.sub.2 O.sub.3                    :Eu.sub.0.004 Nd.sub.0.02                                                                               1170 2104                                      1-3    2SrO.(Mg.sub.0.9 Ba.sub.0.1)O.2SiO.sub.2 0.1B.sub.2 O.sub.3                    :Eu.sub.0.004 Dy.sub.0.02                                                                               836  1706                                      1-4    2(Sr.sub.0.9 Cd.sub.0.1)O.MgO.2SiO.sub.2 0.1B.sub.2 O.sub.3                    :Eu.sub.0.004 Dy.sub.0.02                                                                               1031 1842                                      2-1    2(Ca.sub.0.9 Zn.sub.0.1)O.MgO.2SiO.sub.2 0.1B.sub.2 O.sub.3                    :Eu.sub.0.004 Dy.sub.0.02                                                                               635  784                                       2-2    2CaO.(Mg.sub.0.9 Zn.sub.0.1)O.2SiO.sub.2 0.1B.sub.2 O.sub.3                    :Eu.sub.0.004 Dy.sub.0.02                                                                               703  802                                       2-3    2(Ca.sub.0.95 Ba.sub.0.05)O.MgO.2SiO.sub.2 0.1B.sub.2 O.sub.3                  :Eu.sub.0.004 Nd.sub.0.02                                                                               507  769                                       2-4    2CaO.(Mg.sub.0.9 Be.sub.0.1)O.2SiO.sub.2 0.1B.sub.2 O.sub.3                    :Eu.sub.0.004 Dy.sub.0.02                                                                               603  726                                       3-1    2(Sr.sub.0.495 Ca.sub.0.495 Zn.sub.0.05)O.MgO.2SiO.sub.2.0.1B.sub.2             O.sub.3 :Eu.sub.0.004 Dy.sub.0.02                                                                      1083 2835                                      3-2    2Sr.sub.0.5 Ca.sub.0.5)O.(Mg.sub.0.9 Ba.sub.0.1)O.2SiO.sub.2                   0.1B.sub.2 O.sub.3 :Eu.sub.0.004 Dy.sub.0.02                                                            1017 2786                                      Comparative                                                                           (CaSr)S:Bi               100  100                                       samples                                                                               (ZnCd)S:Cu               100  100                                              ZnS:Cu                   100  100                                       __________________________________________________________________________

3. When M=Ba, a=5, b=0, c=8, R=B₂ O₃, d=0.1, the formula of the phosphors is 5BaO·8SiO₂ 0.1B₂ O₃ :Eu_(x),Ln_(y), the synthesized phosphor, in which x=0.01, Ln=Dy, y=0.02 shows light green luminescence, and the dominant compound is Ba₅ Si₈ O₃₁, the emission spectrum and excitation spectrum are shown in FIG. 17(a), (b), TABLE 11 shows its relative persistence property. Ba being party replaced by one or more elements from a group consisting of Ca, Sr, Mg, Zn, Cd and Be, the phosphors display persistence luminescence too.

                  TABLE 11                                                         ______________________________________                                                     Chemical      Relative afterglow                                               composition   intensity                                            Experiment  formula       10'       60'                                        ______________________________________                                         1-1         Ba.sub.5 Si.sub.8 O.sub.31 :Eu,Dy                                                            87.4      100                                        comparative sample                                                                         ZnS:Cu        100       100                                        ______________________________________                                    

4. When M=Zn, R=B₂ O₃, a=2, b=0, c=1, d=0.1, Ln=Dy and Mn, x=0.01, y=0.02, the synthesized phosphor shows light green afterglow and the main compound is Zn₂ SiO₄. The decay property is shown in TABLE 12. Zn being partly replaced by one or more elements from a group consisting of Ca, Sr, Mg, Ba, Cd and Be the phosphor shows decay luminescence too.

                  TABLE 12                                                         ______________________________________                                                     Chemical      Relative afterglow                                               composition   intensity                                            Experiment  formula       10'       60'                                        ______________________________________                                         1-1         Zn.sub.2 SiO.sub.4 :Eu,Dy,Mn                                                                 32.6      95.8                                       Comparative sample                                                                         ZnS:Cu        100       100                                        ______________________________________                                    

In this invention it is also found that put other additives (0-15% weight of the raw material) to the raw material can more or less improve the long afterglow intensity of phosphor and the quality of the synthesized product, but didn't change its dominant crystal structure and main compound, the influence of the additives on the afterglow property of the greenish-yellow phosphors is indicated in TABLE 13.

In TABLE 13 the greenish-yellow phosphor is selected wherein M=Sr₀.3 Ca₀.7,M'=M,R=B₃ O₃,Ln=Dy,a=2.5,b=1.2,c=2.5,d=0.1,x=0.02,y=0.1

                                      TABLE 13                                     __________________________________________________________________________                                       Relative afterglow                                                     Added   intensity                                    Ex.                                                                               Chemical composition formula                                                                          compound                                                                            Mol                                                                               10' 60'                                      __________________________________________________________________________     1  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               0    0  643 1374                                     2  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub..sub.0.1                                                                          NH.sub.4 Cl                                                                         0.1                                                                               684 1427                                     3  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               NH.sub.4 F                                                                          0.1                                                                               672 1395                                     4  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               Li.sub.2 CO.sub.3                                                                   0.05                                                                              693 1432                                     5  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               SrF.sub.2                                                                           0.1                                                                               675 1398                                     6  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               CaF.sub.2                                                                           0.1                                                                               663 1388                                     7  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               CaSO.sub.4                                                                          0.1                                                                               670 1391                                     8  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               SrSO.sub.4                                                                          0.1                                                                               675 1382                                     9  2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               SrHPO.sub.4                                                                         0.1                                                                               682 1407                                     10 2.5(Sr.sub.0.3 Ca.sub.0.7 O).1.2MgO.2.5SiO.sub.2.0.1B.sub.2 O.sub.3            :Eu.sub.0.02 Dy.sub.0.1                                                                               CaHPO.sub.4                                                                         0.1                                                                               667 1379                                     __________________________________________________________________________

In other chemical formula more or less influence of these additives on the afterglow property is found as well.

The phosphors of this invention have good water resistance property and better stability. In the same condition, putting the long afterglow phosphor of aluminate and along afterglow silicate phosphor of this invention into water respectively it is found that the aluminate's phosphor decomposed after three days and decomposed entirely after a week and losing the luminescent property, but the silicate's phosphor didn't decompose even after three months. The afterglow property still existed.

This invention have the following outstanding features compared with the present technology:

(1) Inventing a new series of long afterglow phosphors with silicate as the dominant host lattice that possesses the fairly good chemical stability and water resistance property, and changeable afterglow colors: bluish-green, green, greenish-yellow and yellow.

(2) Inventing of some ions can enhance the luminescence of the Eu²⁺ and improve the afterglow luminescent properties.

(3) Adding of boron and phosphors compound can make further improvement on the luminescent properties.

The invention is described in detail hereafter by referring to the examples and figures.

EXAMPLES Example 1 2SrO·MgO·2SiO₂ ·0.1B₂ O₃ :Eu₀.004 phosphor's synthesis and analysis results

Match of the raw materials:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Sr       1.996   SrCO.sub.3      294.6 g                                       Mg       1       4MgCO.sub.3.Mg(OH).sub.2.5H.sub.2 O                                                            97.1  g                                       Si       2       SiO.sub.2       120   g                                       B        0.2     B.sub.2 O.sub.3 6.96  g                                       Eu       0.004   Eu.sub.2 O.sub.3                                                                               0.704 g                                       ______________________________________                                    

The above raw material was ground into fine and mixed homogeneously, then placed in alumina crucible and fired in the furnace which full of Nh₃ (g) atmosphere at 1350° C. for 3 hrs, after that cooled down and smashed the fired phosphor, finally sifted it out by the sieve of 100 mesh.

The appearance of this phosphor is greyish white, after irradiated under sun light it can present blue afterglow color in dark; measured the phosphor's luminescent afterglow intensity, show in experiment 1-4 in TABLE 4, FIG. 1 (a), (b) and FIG. 2 are the example phosphor's emission spectrum, excitation spectrum and x-ray diffraction pattern respectively, according to its x-ray diffraction pattern, its crystal structure, is akermanite and its compound is Sr₂ MgSi₂ O₇, the phosphor's chemical formula Sr₂ MgSi₂ O₇ :Eu is defined.

Example 2 2SrO·MgO·2SiO₂ ·0.1B₃ O₃ :Eu₀.04,Dy₀.04 phosphor's synthesis and analysis results

Match of the raw materials:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Sr       1.96    SrCO.sub.3      289.3 g                                       Mg       0.996   4MgCO.sub.3.Mg(OH).sub.2.5H.sub.2 O                                                            96.7  g                                       Si       2       SiO.sub.2       120   g                                       B        0.2     H.sub.2 BO.sub.3                                                                               13.56 g                                       Eu       0.004   Eu.sub.2 O.sub.3                                                                               0.704 g                                       Dy       0.04    Dy.sub.2 O.sub.3                                                                               7.46  g                                       ______________________________________                                    

The above raw material is ground into fine and mixed homogeneously in alcohol solution, after baking, placed in alumina crucible, and fired in a high temperature furnace which full of NH₃ (g) atmosphere at 1350° C. for 3 hrs, after that cooled down, smashed the fired phosphor, finally sifted it out by the sieve of 100 mesh.

The appearance of this phosphor is greyish white, after irradiated under fluorescent lamp, it displays very strong blue afterglow in dark, the phosphor's relative luminescent intensity shown as experiment 3-4 in TABLE4, its intensity is obviously higher than that of example 1; besides, the material's afterglow time is long, see FIG. 7; FIG. 3(a)(b) are phosphor's emission spectrum and excitation spectrum respectively; the phosphor's crystal structure and main compound same as example 1, the phosphor's chemical formula Sr₂ MgSi₂ O₇ :Eu, Dy is defined.

Example 3 SrO·3MgO·2SiO₂ ·0.05P₂ O_(S) :Du₀.004,Nd₀.01 phosphor's synthesis

Match of the raw materials:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Sr       0.993   SrCO.sub.3      146.6 g                                       Mg       2.993   4MgCO.sub.3.Mg(OH).sub.2.5H.sub.2 O                                                            290.6 g                                       Si       2       SiO.sub.2       120   g                                       P        0.1     (NH.sub.4).sub.2 HPO.sub.4                                                                     13.2  g                                       Eu       0.004   Eu.sub.2 O.sub.3                                                                               0.704 g                                       Nd       0.1     Nd.sub.2 O.sub.3                                                                               1.68  g                                       ______________________________________                                    

The above raw material is ground into fine and mixed homogeneously in acetone solution, after baking, placed in alumina crucible, and fired in a furnace which full of H₂ (g) atmosphere at 1350° C. for 3 hrs, after that cooled and smashed the fired phosphor, finally sifted it out by the sieve of 100 mesh.

This phosphor can display stronger blue afterglow after irradiated under ultraviolet lamp, analyzed from x-ray diffraction pattern, its dominant compound is Sr₂ MgSiO₇ and Mg₂ SiO₄, the phosphor's chemical composition formula SrO·3MgO·2SiO₂ ·0.05P₂ O₅ Eu,Nd is defined.

Example 4 2CaO·MgO·2SiO₂ ·0.15B₂ O₃ :Eu₀.04,Dy₀.05 phosphor's synthesis and analysis results

Match of the raw materials:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Ca       1.946   CaCO.sub.3      194.6 g                                       Mg       1       4MgCO.sub.3.Mg(OH).sub.2.5H.sub.2 O                                                            97.1  g                                       Si       2       SiO.sub.2       120   g                                       B        0.3     H.sub.3 BO.sub.3                                                                               18.84 g                                       Eu       0.004   Eu.sub.2 O.sub.3                                                                               0.764 g                                       Dy       0.05    Dy.sub.2 O.sub.3                                                                               9.325 g                                       ______________________________________                                    

The above raw material is ground into fine and mixed homogeneously, then placed in alumina crucible fired in a high temperature furnace which full of 30% H₂ (g)+70% N₂ (g) atmosphere at1320° C. for 5 hrs, after that cooled and smashed the fired phosphor, finally sifted it out by the sieve of 100 mesh.

The appearance of this phosphor is light yellow, after irradiated under fluorescent lamp, it can presents very strong yellow afterglow in dark; the phosphor's relative luminescent intensity shown as experiment 2-3 in TABLE 5, which is obviously stronger than that of experiment 1-4 in TABLE 5, its emission spectrum, excitation spectrum are shown in FIG. 5 (a),(b); the phosphor's afterglow time is long, FIG. 7 is phosphor's afterglow characteristic curve, the phosphor's main crystal structure is akermanite and its compound is Ca₂ MgSi₂ O₇, see FIG. 6, so the phosphor's chemical formula is defined as Ca₂ MgSi₂ O₇ :Eu,Dy.

Example 5 1.5CaO·3MgO·2SiO₂ ·0.15B₂ O₃ :Eu₀.04,Ho₀.08 phosphor's synthesis

Match of the raw materials:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Ca       1.5     CaCO.sub.3      150   g                                       Mg       3       4MgCO.sub.3.Mg(OH).sub.2.5H.sub.2 O                                                            291.3 g                                       Si       2       H.sub.2 SiO.sub.3                                                                              156   g                                       B        0.15    B.sub.2 O.sub.3 10.44 g                                       Eu       0.004   Eu.sub.2 O.sub.3                                                                               0.704 g                                       Ho       0.08    Ho.sub.2 O.sub.3                                                                               15.1  g                                       ______________________________________                                    

The synthesis method of this phosphor is the same as example 1, after irradiated under ultraviolet lamp, this phosphor displays yellow afterglow, according to the x-ray diffraction pattern, its compounds is Ca₂ MgSi₂ O₇,CaMgSiO₄ and Ca₃ Si₂₃ O₇ so the phosphor's chemical composition formula 1.5CaO·3MgO·2SiO₂ ·0.15B₂ O₃ Eu,Ho is defined.

Example 6 2(Sr₀.5 Ca₀.5)O·MgO·2SiO₂ ·0.05B₂ O₃ :Eu₀.005,Dy₀.08 phosphor's syntheses and analysis results

Match of the raw materials:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Sr       1       SrCO.sub.3      147.6 g                                       Ca       1       CaCO.sub.3      100   g                                       Mg       1       4MgCO.sub.3.Mg(OH).sub.2.5H.sub.2 O                                                            97.1  g                                       Si       2       SiO.sub.2       120   g                                       B        0.1     H.sub.3 BO.sub.3                                                                               6.28  g                                       Eu       0.005   Eu.sub.2 O.sub.3                                                                               0.88  g                                       Dy       0.08    Dy.sub.2 O.sub.3                                                                               14.92 g                                       ______________________________________                                    

The above raw material is ground and mixed homogeneously, placed in alumina crucible, fired for 3 hrs at 1300° C. in NH₃ (g) atmosphere, after that cooled down and smashed the fired phosphor, finally sifted it out by the sieve of 100 mesh.

The appearance of this phosphor is light green, after irradiated under fluorescent lamp it displays strong green afterglow. This phosphor's relative afterglow intensity is shown in TABLE 6. The emission spectrum, excitation spectrum and x-ray diffraction pattern of this phosphor are shown in FIG. 8(a),(b) and FIG. 9 respectively. The phosphor's afterglow time is long and FIG. 10 is the afterglow characteristics curve. Its chemical formula (Sr₀.5 Ca₀.5)₂ MgSi₂ O₇ :Eu,Dy is defined.

Example 7 2(Sr₀.25 Ca₀.75)O·MgO·2.3SiO₂ ·0.05P₂ O₅ :Eu₀.01,Nd₀.02 phosphor's synthesis

Match of the raw material:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Sr       0.5     Sr(NO.sub.3).sub.2                                                                             105.8 g                                       Ca       1.5     Ca(NO.sub.3).sub.2.4H.sub.2 O                                                                  354   g                                       Mg       1       Mg(NO.sub.3).sub.2.6H.sub.2 O                                                                  256.4 g                                       Si       2.3     silica gel      138   g                                       P        0.1     NH.sub.4 H.sub.2 PO.sub.4                                                                      11.5  g                                       Eu       0.01    Eu.sub.2 O.sub.3                                                                               1.76  g                                       Nd       0.02    Nd.sub.2 O.sub.3                                                                               3.36  g                                       ______________________________________                                    

The synthesis method of this phosphor is the same as described in example 1.

This phosphor displays greenish-yellow afterglow after irradiated under fluorescent lamp. The x-ray diffraction pattern of this phosphor is similar to FIG. 9, so it can be deduced that its compound is (Sr₀.25 Ca₀.75)₂ MgSi₂ O₇, its chemical formula (Sr₀.25 Ca₀.75)₂ MgSi₂ O₇ :Eu,Nd. is defined.

Example 8 3SrO·MgO·2SiO₂ :Eu₀.001, Ho₀.08 phosphor's synthesis

Match of the raw material:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Sr       3       Sr(NO.sub.3).sub.2                                                                             634.8 g                                       Mg       1       MgO             40.3  g                                       Si       2       H.sub.2 SiO.sub.3                                                                              156   g                                       Eu       0.01    Eu.sub.2 O.sub.3                                                                               1.76  g                                       Ho       0.08    Ho.sub.2 O.sub.3                                                                               15.1  g                                       ______________________________________                                    

The synthesis method of this phosphor is the same as described in example 1.

This phosphor displays blue afterglow after irradiated under sunlight, its dominant compound is Sr₃ MgSi₂ O₈, the secondary is Sr₂ MgSi₂ O₇, so the chemical formula Sr₃ MgSi₂ O₈ :Eu,Ho is defined.

Example 9 2(Sr₀.6 Ca₀.4)O·(Mg₀.8 Cd₀.2)O·2.5SiO₂ ·0.01B₂ O₃ :Eu₀.001 Dy₀.02 Bi₀.01 phosphor's synthesis

Match of the raw material:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Sr       1.3     SrCO.sub.3      177.1 g                                       Ca       0.8     CaCO.sub.3      80    g                                       Mg       0.8     4MgCO.sub.3.Mg(OH).sub.2.5H.sub.2 O                                                            77.7  g                                       Cd       0.2     CdO             25.7  g                                       Si       2.5     SiO.sub.2       150   g                                       B        0.2     B.sub.2 O.sub.3 6.96  g                                       Eu       0.01    Eu.sub.2 O.sub.3                                                                               1.76  g                                       Dy       0.02    Dy.sub.2 O.sub.3                                                                               3.73  g                                       Bi       0.01    Bi.sub.2 O.sub.3                                                                               2.33  g                                       ______________________________________                                    

Doped 5% NH₄ Cl by weight of the raw material, grinding and mixing them together, then firing them as example 1.

The fired phosphor displays strong bluish-green afterglow after irradiated under sunlight.

Example 10 5BaO·8SiO₂ ·0.1B₂ O₃ :Eu₀.01 Dy₀.02 phosphor's synthesis

Match of the raw material:

    ______________________________________                                         Element  Mol     Raw Material    Weight                                        ______________________________________                                         Ba       5       BaCO.sub.3      985   g                                       Si       8       SiO.sub.3       480   g                                       B        0.2     B.sub.2 O.sub.3 6.96  g                                       Eu       0.01    Eu.sub.2 O.sub.3                                                                               1.76  g                                       Dy       0.02    Dy.sub.2 O.sub.3                                                                               3.73  g                                       ______________________________________                                    

The synthesis method of this phosphor is the same described in example 1, after irradiated under sunlight this phosphor displays light green persistence, its compound is Ba₅ Si₈)₂₁ and so the chemical formula Ba₅ Si₈ O₂₁ :Eu,Dy is defined.

INDUSTRIAL APPLICATION

The products in this invention can be widely used in all kinds of long afterglow products as indicators or ornaments in dark environment, combined with paint; plastics; printing ink; rubber etc., this series of luminescent materials has good effect in architecture, traffic, decoration, watch and clock dials, fishing tackles, toys and other goods for daily use, it's specially suitable for the production of long afterglow safety products, such as warning, mandatory and escape-route signs. 

What is claimed is:
 1. A long afterglow luminescent material, comprising silicates with activators, wherein said luminescent material has a chemical composition of:aMO·bM'O·bM'O·cSiO₂ ·dR:Eu_(x),Ln_(y), wherein M represents one or more elements selected from the group consisting of Sr, Ca, Ba and Zn; M' represents one or more elements selected from the group consisting of Mg, Cd and Be; R represents one or two components selected from B₂ O₃ and P₂ O₅ ; Ln represents one or more elements selected from the group consisting of Nd, Dy, Ho, Tm, La, Pr, Tb, Ce, Mn, Bi, Sn and Sb; and wherein a, b, c, d, x, and y represent mole coefficients, wherein 0.6≦a≦6, 0≦b≦5, 1≦c≦9, 0≦d≦0.7, 0.00001≦x≦0.2, and 0<y≦0.3; with the proviso that when Ln includes Bi, Mn or Sn, d≠0; and said luminescent material is capable of emitting an emission spectrum ranging from 420 nm to 650 nm when excited by short wavelength light ranging from 250 nm to 500 nm, with a peak position of the emission spectrum ranging from 450 nm to 580 nm, and wherein the long afterglow luminescent color of said luminescent material is blue, bluish-green, green, greenish-yellow or yellow.
 2. The long afterglow luminescent material of claim 1, wherein M represents one or two elements selected from Sr and Ca; M' represents Mg; R represent one or two components selected from B₂ O₃ and P₂ O₅ ; Ln represents one or more elements selected from the group consisting of Nd, Dy, Ho, Bi and Sn, wherein 0.6≦a≦4, 0.6≦b≦4, 1≦c≦5, and 0≦d≦0.4.
 3. The long afterglow luminescent material of claim 2, wherein 0-40% mole of the elements M and/or M' have been replaced by one or more elements selected from the group consisting of Ba, Zn, Cd and Be.
 4. The long afterglow luminescent material of claim 1, wherein said luminescent material has a chemical composition of:M₂ MgSi₂ O₇ :Eu_(x), Ln_(y) or M₃ MgSi₂ O₈ :Eu_(x), Ln_(y), wherein 0.00001≦x≦2, 0<y≦0.3; M represents Sr_(1-Z) Ca_(Z) ; and Ln represents one or more elements selected from the group consisting of Nd, Dy, Ho, Tm, La, Pr, Tb, Ce and Sb.
 5. The long afterglow luminescent material of claim 1, wherein said luminescent material has a chemical composition of:Ba₅ Si₈ O₂₁ dR:Eu_(x),Ln_(y), wherein R represents one or two components selected from B₂ O₃ and P₂ O₅ ; and wherein d, x and y represent mole coefficients, wherein 0<d≦7, 0.00001≦x≦0.2, and 0<y≦0.3.
 6. The long afterglow luminescent material of claim 1, wherein said luminescent material has a chemical composition of:Zn₂ SiO₄ dR:Eu_(x),Dy_(y),Mn_(y), wherein R represents one or two components selected from B₂ O₃ and P₂ O₅ ; and wherein d, x and y represent mole coefficient, wherein 0<d≦0.7, 0.00001≦x≦0.2, and 0<y≦0.3.
 7. A method of manufacturing the long afterglow luminescent material of claim 1, wherein M, M', Ln and Eu are derived from raw materials individually selected from the group consisting of one or more of a carbonate, sulphate, nitrate, phosphate, borate, acetate, oxalate, citrate, oxide, hydroxide and halogenide, including mixtures thereof; and whereinSi is derived from SiO₂, silicic acid, silica gel or silicate; R is derived from a compound containing B or P, with the proviso that such a compound can form B₂ O₃ and P₂ O₅ in a subsequent sintering procedure; the method comprising the following steps:weighing, grounding, and homogeneously mixing raw materials comprising M, M', Ln, Eu, Si and R to yield a mixture; sintering the mixture at a temperature between 1100-1400° C. for a period of about 2 to 50 hours under a reducing atmosphere to yield a fired mixture; milling and sifting the fired mixture into a desired particle size.
 8. The method of manufacturing the long afterglow luminescent materials of claim 7, wherein the reducing atmosphere is selected from the group consisting of H₂, NH₃, and N₂ in combination with H₂.
 9. The method of manufacturing the long afterglow luminescent material of claim 7, wherein NH₄ F, Li₂ CO₃, SrF₂, CaF₂, CaSO₄, SrSO₄, SrHPO₄, or CaHPO₄ has been added to the mixture to participate in a solid-phase reaction. 